I can't help you but people who might would probably want to know if the plot next door going to be built on and where you are situated geographically.

I'd start by zoning. Your probably want your dining area near the door closest to the kitchen. I'd probably put a patio in the square made between the back of the house on the right and the back of the house on the left. If you want space to play ball games, you have to figure out the size you need.

To have a nice sitting area, you need some plants. I'd probably put it in the upper left corner.